After some nasty tasting beer, I am now more concerned then ever with sanitation. I bought some foam stoppers from Northern Brewer to be used on my yeast starters replacing the aluminum foil I had been using.

In the past, I prepared my starter by boiling the DME directly in the flask on the stove. These foam stoppers are advertised as able to withstand boiling or autoclaving temperature.

Do you guys think I can still boil my starter in the flask on the stove with these foam stoppers attached?

When I have boiled directly in the flask, I leave the stopper in place so the escaping steam passes through it - seems that would do a decent job of sanitizing it. Alternatively, it's a pretty simple matter to saturate the foam with starsan and then squeeze out the excess (preferably with a gloved hand or similar...)